Figure 6. Schematic model suggesting the presence of the entire exocyst complex on exocytic vesicles.

Exocytic vesicles labeled with the exocyst holocomplex may reach cell poles through one of two alternative routes: they are either transported along actin cables by myosin V Myo52 or reach cell poles by random walk. At the cell poles, Sec3 and Exo70 tether the exocyst complex and the vesicle by binding PIP₂ and Rho proteins. In absence of myosin V transport (myo52Δ), vesicles and the entire exocyst reach the pole by random walk. In absence of both Sec3 and Exo70, vesicles and the rest of the exocyst complex fail to be tethered at cell poles and form aggregates. Exo represents Sec5, Sec6, Sec8, Sec10, Sec15 and Exo84.